
if (document.images) 
    {
        alert("loading...");
// precache all ‘off’ button images
var offImgArray = new Array()
offImgArray["play"] = new Image(75,105);
offImgArray["play"].src="images/Courses_off.jpg";

var onImgArray = new Array()
onImgArray["play"] = new Image(75,105);
onImgArray["play"].src="images/Courses_on.jpg";
}

function imageOn(imgName)
{
    
    if (document.images) 
    {
        document.images[imgName].src = onImgArray[imgName].src;
    }
}
function imageOff(imgName) 
{
    if (document.images) 
    {
    document.images[imgName].src = offImgArray[imgName].src;
    }
}

function setMsg(msg) 
{
window.status = msg
return true
}
// load an image chosen from select list
function loadCached(list) 
{
var img = list.options[list.selectedIndex].value
document.thumbnail.src = eval(img + ".src");
return setMsg("hello");
}
